Types of Reactions

• Synthesis Reaction
  In a synthesis reaction two or more chemical species combine to form a more complex product.
  
  A + B ----> AB
  
  The combination of iron and sulfur to form iron (II) sulfide is an example of a synthesis reaction:
  
  8 Fe + S8 ----> 8 FeS

• Decomposition Reaction
  In a decomposition reaction a compound is broken into smaller chemical species.
  
  AB ---> A + B
  
  The electrolysis of water into oxygen and hydrogen gas is an example of a decomposition reaction:
  
  2 H2O ---> 2 H2 + O2

• Single Displacement
  A substitution or single displacement reaction is characterized by one element being displaced from a compound by another element.
  
  A + BC ---> AC + B
  
  An example of a substitution reaction occurs when zinc combines with hydrochloric acid. The zinc replaces the hydrogen:
  
  Zn + 2 HCl ---> ZnCl2 + H2

• Double Displacement Reaction
  In a double displacement or metathesis reaction two compounds exchange bonds or ions in order to form different compounds.
  
  AB + CD ---> AD + CB
  
  An example of a double displacement reaction occurs between sodium chloride and silver nitrate to form sodium nitrate and silver chloride.
  
  NaCl(aq) + AgNO3(aq) ---> NaNO3(aq) + AgCl(s)

• Neutralization Reaction or Acid-Base Reaction
  An acid-base reaction is type of double displacement reaction that occurs between an acid and a base. The H+ ion in the acid reacts with the OH- ion in the base to form water and an ionic salt:
  
  HA + BOH ---> H2O + BA
  
  The reaction between hydrobromic acid (HBr) and sodium hydroxide is an example of an acid-base reaction:
  
  HCl + NaOH ---> NaCl + H2O

• Combustion
  A combustion reaction is a type of redox reaction in which a combustible material combines with an oxidizer to form oxidized products and generate heat (exothermic reaction). Usually in a combustion reaction oxygencombines with another compound to form carbon dioxide and water. An example of a combustion reaction is the burning of naphthalene:
  
  C10H8 + 12 O2 ----> 10 CO2 + 4 H2O

• Isomerization
  In an isomerization reaction, the stuctural arrangement of a compound is changed but its net atomic composition remains the same.

• Hydrolysis Reaction
  A hydrolysis reaction involves water. The general form for a hydrolysis reaction is:
  
  X-(aq) + H2O(l) <--> HX(aq) + OH-(aq)

• Oxidation-Reduction or Redox Reaction
  In a redox reaction the oxidation numbers of atoms are changed. Redox reactions may involve the transfer of electrons between chemical species.
  
  The reaction that occurs when In which I2 is reduced to I- and S2O32- (thiosulfate anion) is oxidized to S4O62- provides an example of a redox reaction:
  
  2 S2O32−(aq) + I2(aq) ---> S4O62−(aq) + 2 I−(aq)